Tobacco and flavoring composition



United States Patent Ofl ice 3,124,140 Patented Mar. 10, 1964 3,124,140 TGBACCG AND FLAVQRENG CQMPGSKTIUN James Donaid Fredrickson, Winston-Salem, N.C., assignor to R. J. Reynolds Tobacco Company, Winston-Salem, N.C., a corporation of New Jersey No Drawing. Filed Feb. 6, 1963, Ser. No. 256,528 16 Claims. (Cl. 131-17) This invention relates to a tq'bacco product and has for an object the provision of a Composition and process for improving the flavor and aroma of tobacco smoke.

It is well known in the tobacco art that the flavor and aroma of the smoke from a tobacco product are very important considerations in so far as the ultimate consumer is concerned. Considerable efforts are exerted by the manufacturers of tobacco products to provide a product that will be acceptable to the consumer, particularly as regards flavor and aroma characteristics. It has been the common practice in the tobacco industry to prepare blends of domestic and oriental tobaccos in order to provide smoking tobacco which has a pleasant flavor and aroma during smoking of the product. However, such a procedure is costly and may at times become prohibitive in the event that certain types of tobacco may be in short supply. Accordingly, it is a further object of this invention to provide a new class of additive materials which when applied to the tobacco products improve and enhance the flavor and aroma of the smoke emitted therefrom thereby increasing or enhancing the pleasure and other values that may be derived by the consumer from the use of these products.

A further object of this invention is the provision of a process for enhancing or otherwise improving the flavor, aroma and other qualities of the smoke from certain domestic, oriental, reconstituted or synthetic tobaccos which may be deficient in said flavor or aroma or other qualities.

A still further object of this invention is the provision of smoking products, such as cigarettes, cigars or pipe tobacco, and a process for forming same whereby their flavor and aroma during smoking are improved or enhanced.

Further and additional objects will appear from the following description and the appended claims.

In accordance with one embodiment of this invention, a tobacco product is provided to which has been added or which has been treated with a small amount of a compound selected from the group consisting of substituted malic acids having the formula and the nontoxic salts and anhydrides thereof wherein R is hydrogen or lower alkyl, R is hydrogen, lower alkyl or benzyl, R is hydrogen or lower alkyl and at least one of R R or R is other than hydrogen. Compounds falling within the above generic formula include 2-methylrnalic acid, 2,3-dimethylmalic acid, 3-ethyl-2-methylmalic acid, 2-methyl-3-propylmalic acid, 3-isopropyl-2- methylmalic acid, 3-butyl-2-methylmalic acid, 3-benzyl- Z-methylrnalic acid, B-methylmalic acid, 3-ethylmalic acid and trimethylmalic acid. Also included are the anhydn'des or salts of these acids including sodium, potassium, calcium, iron or the like. In the foregoing generic formula the lower alkyl radicals where present preferably have not more than four carbon atoms.

The compounds comprehended within the scope of this invention are essentially nonvolatile and do not per se provide flavor or aroma to the tobacco product. However, when they are incorporated into tobacco products,

they impart a desirable flavor and aroma to the smoke which many smokers have found to be desirable. Each of the specific compounds imparts its own particular flavor or aroma when smoked and it has not been possible to define or to assign a quality which is common to or descriptive of the flavor or aroma emitted from all of the compounds embraced herein. It is pointed out that the methods for characterizing or defining the quality of flavor or aroma in tobacco smoke are almost purely subjective and different smokers may define the same flavor quite diiferently. Some are sweet and tend to be acid or spicy in nature while others are mellow or provide a burnt flavor which may have a fruity note as will hereafter he described in connection with a number that have been tested.

Certain of the additives comprehended within the scope of this invention are known compounds and may be prepared by conventional procedures. Others, however, have not been reported in the literature. For a fuller understanding of this invention reference will be made to a procedure which is adaptable for preparing certain of the 2-alkyl substituted malic acids. The method illustrated involves the following reaction scheme:

NaCN

| ON 020211 1120 cont 002K in which R is lower alkyl, R is lower alkyl or benzyl as above defined and X is halogen. Throughout this specification when temperatures are indicated it will be understood that they are expressed in degrees centigrade.

One specific example is as follows: Anhydrous ethanol (500 ml.) was distilled into a 1 liter round-bottomed flask fitted with a mechanical stirrer and a reflux condenser, the upper end of which was protected by a calcium chloride tube. Metallic sodium (23 g.) was added to the anhydrous ethanol over a period of three hours. After the sodium had dissolved, ethyl acetoacetate (130 g.) was added to the solution through a separatory funnel. The stirrer was started and the solution heated to gentle boiling. Ethyl bromide g.) was added dropwise to the boiling solution over a period of 3.5 hours. The stirred reaction mixture was heated under reflux for 9 hours, cooled to room temperature, filtered and concentrated to 250 ml. Dilution of the residue with Water (200 ml.) resulted in the formation of two liquid phases which were separated. The aqueous phase was extracted with three volumes (100 m1.) of ether. The ether extract was combined with the organic phase, washed with three volumes (100 ml.) of water and dried with anhydrous sodium sulfate. The crude ethyl 2-ethylacetoacetate after removal of the ether Weighed g. (79 percent yield).

A mixture of ethyl Z-ethylacetoacetate (47.4 g.), potassium dihydrogen phosphate (82.0 g), and water (120 ml.) was cooled to 10-15 A solution of 95 percent sodium cyanide (34.8. g.) in water ml.) was added to the mixture with vigorous stirring. The mixture was stirred at 10-20 for one hour, filtered, and extracted with five volumes (100 ml.) of ether. The ether extract was extracted with 2 N hydrochloric acid (50 ml.) and with four volumes (50 ml.) ()Ef water, diluted with pentane (300 ml.) and dried with anhydrous sodium sulfate. After removal of the solvent by distillation, the crude cyanohydrin weighed 48.9 g. (88 percent of the theoretical yield).

The crude cyanohydrin was heated with concentrated hydrochloric acid (2.5 moles .per mole of cyanohydrin) in a water bath at 85-100 for approximately 48 hours. The hydrolysis mixture was extracted with three volumes s ears-o (100 ml.) of hexane and then extracted continuously with ether to isolate the substituted malic acid. The crude 3- ethyl-2 rnethylmalic :acid was crystallized from benzenechloroform. The product was a mixture of two racemates which were separated by fractional crystallization from chloroform. The less soluble racemate melted at l42.0143.0 C. The other racemate melted at 101.0- 103.0 C. The mixture of racemates may be used as an additive in accordance with this invention without further treatment.

Other disubstituted malic acids have also been prepared in accordance with the above procedure wherein R is lower 'alkyl and R is lower alkyl or benzyl. The products were mixtures of racemates which, if desired, may be separated by fractional crystallization. However, the racemic mixtures are usable as additives without further treatment.

Also certain of the substituted malic acids of this invention may be prepared in accordance with the following scheme:

0.11m CIQCHO mornooon),

HOCIi-CIIR KOII Hocn01im I 0013 00011 I1 COOII COOH One specific procedure is as follows: A solution of ethylmalonic acid (12.4 g.) and chloral ml.) in anhydrous pyridine (50 ml.) was heated at 70-75" for 7.5 hours. The pyridine and unreaoted chloral were distilled from the reaction mixture at 65 and reduced pressure. The residue was treated with 18 percent hydrochloric acid (100 ml.) and the aqueous mixture extracted with five volumes (200 ml.) of ether. The ether extract was extracted with two volumes (100 ml.) of water, diluted with pentane, dried with anhydrous sodium sulfate and distilled at reduced pressure. The residue (6.49 g.) in acetone (200 ml.) was percolated through a bed of Darco G60 x mm.) on a bed of Celite (15 x 45 mm.) in a sintered glass filter funnel. The Darco G-60 was rinsed with acetone m l.). Aiter removal of the acetone by distillation at reduced-pressure, the crude 2-ethyl- 3-hydroxy-4-trichlorobutanoic acid weighed 4.95 g.

The crude trichloroacid and a solution of potassium hydroxide (7.5 g.) in water ml.) were heated at for 2 hours. The mixture was cooled to room temperature, and acidified with concentrated hydrochloric acid (pH of less than 2). The acidified mixture was extracted continuously with ether for 25 hours. After the ether had been removed by distillation, the residue (3.72 g.) was dissolved in ace-tone (250 ml.). The acetone solution was percolated through a bed of Darco G-60 (27 X 45 mm.) on a bed of Celite (15 x 45 mm.) in a sinte-red filter funnel to remove the highly colored materials. After the acetone had been removed by distillation, the crude 3-ethylrnalic acid weighed 3.55 g. (23 percent of the theoretical amount based on the original ethylmalonic acid). The crude 3-ethylmalic acid which was a mixture of racemates was crystallized from chloroform-acetone. The first crop of crystals melted at 102.0- 105.0 C. The second crop melted at 1060-1080 C. These products are usable additives without further treatment.

It will be apparent that other 3-substituted malic acids can be prepared utilizing the above procedure by an appropriate selection of the substituted malonic acid starting material.

In accordance with this invention, the compounds comprehended herein are added to tobacco or applied to a smokin article or its component parts in amounts to provide a product which contains the additive in the amount of about 0.0001 to 0.5 percent by weight of the product. Preferably the amount of additive is between about 0.001 and 0.25 percent by weight in order to provide a tobacco product having a desired flavor and aroma. Mixtures of additives may be used and the amount will depend upon the amount of flavor or aroma desired in the smoke and the particular compound that is used. The additive may be applied to the tobacco in any suitable manner and preferably in the form of a liquid dispersion, such as a solution or suspension, by spraying, dipping or otherwise. The additive may be incorporated at any step in the treatment of the tobacco but is preferably added after aging, curing and shredding and before the tobacco is formed into cigarettes. Likewise it will be apparent that only a portion of the tobacco need be treated and the thus treated tobacco may be blended with other tobaccos before the cigarettes or other smoking articles are formed. In such case the tobacco treated may have the additive in excess of the amounts above indicated so that when blended with other tobaccos the final product will have the percentage within the indicated range.

In accordance with one specific example of this invention, shredded, aged flue-cured tobacco is sprayed with a 1% acetone solution of 3-ethyl2-methylmalic acid in an amount to provide a tobacco containing 0.005 percent by weight of the additive on a dry basis. Thereafter the acetone is removed by evaporation and the tobacco is manufactured into cigarettes by the usual techniques. It has been found that the smoke from a cigarette when prepared as indicated has a desired and pleasing flavor and aroma which to som people is buttery acid with sweet and peppery notes which are detectable and pleasing in the main and side smoke streams when the cigarette is smoked. The following table indicates the flavor imparted to tobacco smoke by certain of the compounds comprehended within the scope of this invention.

Flavors Imported t0 Tobacco Smoke by Substituted Malic/Acids 2 methyl 3 propylmalic acid Heavy mellow acid with balsamic and cinnamon-like notes.

3 isopropyl 2 methylmalic acid Buttery acid with peppery and walnut notes.

Weak mellow acid with a balsamic note,

3 butyl 2 methylma'lic acid 3 benzyl 2 methylmalic acid Sweet acid with strong balsamic and cinnamon notes, reminiscent of flavor imparted to smoke by sweet gum and rabbit tobacco. Prunes and burnt dried apples. Sweet, penetrating acid with acrylic and heavy mossy notes Weak acid with a balsamic note reminiscent of rabbit tobacco.

Enhanced the flue-cured tobacco smoke flavor more than the other compounds.

The flavors imparted to the smoke from flue-cured and burley tobaccos were similar.

The racemate. M.P. 142.0143.0, was used in this test. The flavor produced by the raccmate, M.P. 1010-1030 was weaker and lacked the distinct sweet note.

The additives falling within the scope of this invention are preferably applied to the tobacco by spraying, dipping or otherwise, utilizing suitable suspensions or solutions of the additive. Thus water or volatile organic solvents, such as alcohol, ether, acetone, volatile hydrocarbons and the like, may be used as the carrying medium for the additive while it is being applied to the tobacco. Under certain conditions the additives may be sprinkled or dusted on the tobacco alone or with a suitable carrier. Also other fiavorand aroma-producing additives, such as those disclosed in United States Patents Nos. 2,766,145, 2,905,- 575, 2,905,576, 2,978,365 and 3,041,211 may be incorporated into the tobacco with the additive of this invention.

3-methylmalic acid 3-ethylmalic acid Trimethylmalic acid Also it will be appreciated that the compounds comprehended within the scope of this invention contain at least one asymmetric carbon atom and that stereomers are possible. The chemical methods used for preparing the compounds are not generally stereo specific. Accordingly, the several racemates of the compounds and their mixtures are included as tobacco additives within the scope of this invention.

In the event that the anhydrides or nontoxic salts of the compounds are to be used, they are formed by conventional methods applicable to dicarboxylic acids of this general type. They are incorporated into the tobacco or added to the tobacco product in the same manner generally indicated above and also provide the desired flavor and aroma to the tobacco when smoked.

While this invention is principally useful in the manufacture of cigarette tobacco, it is also suitable for use in connection with the manufacture of pipe tobacco, cigars or other tobacco products. Furthermore, the compounds may be added to certain tobacco substitutes of natural or synthetic origin and by the term tobacco as used throughout this specification is meant any composition intended for human consumption by smoking or otherwise, whether composed of tobacco plant parts or substitute materials or both. Also the invention has been particularly described with reference to the addition of the compounds directly to tobacco. However, it will be apparent that the compound or mixtures thereof may be applied to the paper of the cigarette or to the wrapper of a cigar. Also it may be incorporated into the seam paste employed for gluing the cigarette paper. Thus a tobacco product is provided which includes the specified additives and tobacco although in every instance the compound need not be admixed with the tobacco as above specifically described.

While several particular embodiments of this invention are shown above, it will be understood, of course, that the invention is not to be limited thereto, since many modifications may be made, and it is contemplated, therefore, by the appended claims, to cover any such modifications as fall within the true spirit and scope of this invention.

I claim:

1. A smoking product having incorporated therewith a small amount of a compound which enhances the flavor and aroma of the smoke from said product, said compound being selected from the group consisting of substituted malic acids having the formula w r IRA-C (ii-R OOH COOH and the nontoxic salts and anhydrides thereof wherein R is hydrogen or lower alkyl, R is hydrogen, lower alkyl or benzyl, R is hydrogen or lower alkyl and at least one of R R or R is other than hydrogen.

3. A tobacco product having added thereto 3-ethyl-2- methylmalic acid in an amount suflicient to enhance the flavor and aroma of the product when smoked.

4. A tobacco product having added thereto 3-ethylmalic acid in an amount suflicient to enhance the flavor and aroma of the product when smoked.

5. A tobacco product having added thereto 3-isopropyl- 2-methylmalic acid in an amount sufficient to enhance the flavor and aroma of the product when smoked.

6. A tobacco product having added thereto 3-methyl-3- n-propylmalic acid in an amount sufficient to enhance the flavor and aroma of the product when smoked.

7. A tobacco product having added thereto 3-benzyl-2- methyhnalic acid in an amount suflicient to enhance the flavor and aroma of the product when smoked.

8. A tobacco product having added thereto 2,3-dimethylmalic acid in an amount suflicient to enhance the flavor and aroma of the product when smoked.

9. A process for enhancing the flavor and aroma of the smoke from a tobacco product which comprises adding to said product a compound selected from the group consisting of substituted malic acids having the formula 600E (EOOH and the nontoxic salts and anhydrides thereof wherein R is hydrogen or lower alkyl, R is hydrogen, lower alkyl or benzyl, R is hydrogen or lower alkyl and at least one of R R or R is other than hydrogen.

10. A process of enhancing the flavor and aroma of the smoke from tobacco which comprises adding to said tobacco between about 0.0001 and 0.5 percent by weight in the form of a liquid dispersion of a compound selected from the group consisting of substituted malic acids having the formula OH R LE8 JJOOH DOOH and the nontoxic salts and anhydrides thereof wherein R is hydrogen or lower alkyl, R is hydrogen, lower alkyl or benzyl, R is hydrogen or lower alkyl and at least one of R R or R is other than hydrogen.

11. A process of enhancing the flavor and smoke from tobacco which comprises adding to said tobacco a small amount of 3-ethyl-2-methylrnalic acid.

12. A process of enhancing the flavor and smoke from tobacco which comprises adding to said tobacco a small amount of 3-cthylmalic acid.

13. A process of enhancing the flavor and smoke from tobacco which comprises adding to said tobacco a small amount of 3-isopropyl-2-methylmalic acid.

14. A process of enhancing the flavor and smoke from tobacco which comprises adding to said tobacco a small amount of 3-methyl-3-n-propylmalic acid.

15. A process of enhancing the flavor and smoke from tobacco which comprises adding to said tobacco a small amount of 3-benzyl-2-methylmalic acid.

16. A process of enhancing the flavor and smoke from tobacco which comprises adding to said tobacco a small amount of 2,3-dimethylmalic acid.

References Cited in the file of this patent UNITED STATES PATENTS 1,920,588 Pacini Aug. 1, 1933 2,766,145 Jones Oct. 9, 1956 2,766,146 Ashburn Oct. 9, 1956 2,869,557 Teague Jan. 20, 1959 

1. A SMOKING PRODUCT HAVING INCORPORATED THEREWITH A SMALL AMOUNT OF A COMPOUND WHICH ENHANCES THE FLAVOR AND AROMA OF THE SMOKE FROM SAID PRODUCT, SAID COMPOUND BEING SELECTED FROM THE GROUP CONSISTING OF SUBSTITUTED MALIC ACIDS HAVING THE FORMULA 